If you have access to the ceiling void above the bathroom, The Vents Turbo Tube Inline Ceiling Fan is by far the best solution to the problem of bathroom steam.
Inline fans are typically way more powerful than standard wall mounted axial fans. Extracting 565m3/hr, the six inch Turbo Tube Pro 150 vastly outperforms axial fans of the same size. Indeed this extraction rate is suitable for the biggest bathrooms or wet rooms and may even be used in small commercial situations.
This model features an over run timer which ensures all moisture is extracted even after manual power to the fan has been cut. Set on install, the timer is adjustable from 2 - 20 minutes.
One of the biggest benefits of an inline fan, however, is the fact that the fan itself and therefore all electrics and electrical connections are housed outside the bathroom, whilst the ventilation point can be anywhere in the bathroom, extracting steam at source. In this sense it is an 'All Zone Bathroom Fan' but does not require a 12v transformer.
||1. The Turbo Tube, sits above the bathroom in the length of ducting (from which it derives the term 'inline'). The fan can sit anywhere within this duct run - performance is not affected.
2. Ducting is attached to the 'extract spigot' and runs to an internal grille in the ceiling. In our diagram there are two internal venting points in the same room. Your venting point can be directly above the shower or bath, thus extracting steam at source.
3. Ducting is attached to the 'exhaust spigot' and goes to your external grille on the outside wall. The total duct run from bathroom ceiling to outside wall should not exceed 10m and we recommend keeping it as straight as possible to minimise air pressure, which improves efficiency.